Facing millions of dollars in cuts in both federal and city funding, local prosecutors are scrambling to find ways to avoid significantly reducing the size of proven crime-fighting programs.

The federal government in December signed off on slashing by 67% its funding for one of the country’s largest law enforcement grant programs, the Edward Byrne Memorial State and Local Law Enforcement Assistance Grant Program, which for years has funded specialized task forces within the offices of the city’s five district attorneys to fight a broad spectrum of crimes, such as narcotics trafficking, gang activity, and identity theft. The program is named for a city police officer who was gunned down in the Bronx while guarding a witness who had agreed to testify against a group of drug dealers.

With the mayor’s fiscal year 2009 budget calling for 6% cuts to the funding for the district attorneys, prosecutors are foreseeing disaster.

“This is going to have devastating effects,” District Attorney Charles Hynes of Brooklyn said. “We depend on funds from the Byrne grants for our gang and narcotics investigations and to run a number of prevention programs throughout Brooklyn.”

The cuts to Byrne grants were precipitated last year when President Bush threatened to veto the Commerce-Justice-Science Appropriations Bill for fiscal year 2008, which included $660 million in funding for the program. In response, Congress passed the Omnibus Appropriations Bill, signed by Mr. Bush in December, that slashed funding for Byrne grants by about $490 million.

Due to the cuts, New York State will lose out on $17 million in funding.

Several of the city’s district attorneys have already begun lobbying lawmakers to have the funding restored. Mr. Hynes said he traveled to Washington, D.C., last week to drum up support.

Among a number of concerns regarding the cuts, District Attorney Robert Johnson of the Bronx is worried he may have to reduce his staff.

“We’ve used Byrne money to create a full fledged gang bureau that employs several prosecutors,” Mr. Johnson said. “Whether it be in the gang bureau or elsewhere, we’re going to have to make reductions.”

Mr. Johnson said his office would receive about $600,000 less in Byrne grants than it has in previous years, and if Mayor Bloomberg’s proposed budget passes in the City Council, he is expecting to be out another $2.86 million in funding in fiscal year 2009.

In Manhattan, Byrne grants have in recent years helped fund a variety of investigative programs within the district attorney’s office, including cold case, child abuse, witness protection, and identity theft initiatives. The office in fiscal year 2009 will receive $416,000 in Byrne grants, compared with $1.26 million the previous year.

While the city’s prosecutors have yet to feel the effects of the cuts, they have been put on notice by the state that they will begin to receive the reduced grant awards in April.

The commissioner of the state’s division of criminal justice services, Denise O’Donnell, with the support of Governor Spitzer, is pushing Congress to reverse the cutbacks.

“We are very proud of the crime reductions in New York City and we have to continue to fund these programs that have proven to be effective,” Ms. O’Donnell said.

District Attorney Richard Brown of Queens, whose office will lose out on about $1 million in Byrne grants that have funded gun and narcotics trafficking operations, said the cuts could prove to be irresponsible.

“While I recognize the serious financial difficulties in the years ahead, it’s penny wise and pound foolish to attempt to remedy the situation by cutting public safety dollars to the point where our ability to maintain the gains of the last decade are in jeopardy,” he said.